Poor workmanship

In May 2015 I damaged by cars front bumper and I was referred to Targa Panel beaters, in Centurion, by myInsurance for some minor repairs. In October 2017 the paint started to peal off and in November I took it back to Targa. I was told by Freddie that this is not poor workmanship or poor quality and it does happen when there is a chip on the car and it is then washed with the normal type of water pressure hoses, the water will strip the paint. I told them that, if this was the case, then every car's paint should peal off, as every car do pickup minor stone chips on our road. I also told them that it is interesting that in all the years my car never did this, until they have resprayed my car. I went back to my insurance who requested that I obtain the opinion from another pane beater, which I did. As a matter of fact two other panel beaters confirmed that it looks like the primer used, were not properly dried before the painting was done., hence the reason for the paint now pealing of. I went back to my insurance who contacted Target. Targa then request me to take the car to them for another inspection and then promised feedback after one week. I contacted them every week and only after three weeks they told me that they stand by their initial view that is not poor quality or workmanship. I have now gone back to my insurance with their final response and a request to stop business with Targa Panel Beaters.